Some argue Clinton's change of heart on her country's Iraq war is a campaign tactic rather than a sincere move.

The United States presidential candidate Hillary Clinton told reporters on Tuesday that her vote in favor of the U.S.-led war in Iraq back in 2003 was a “mistake”. According to recent study by university researchers in the United States, Canada and Baghdad in cooperation with the Iraqi Ministry of Health, the war claimed the lives of more than half a million people.

“I made it very clear that I made a mistake, plain and simple. And I have written about it in my book, I have talked about it in the past,” Clinton told reporters at an event in Cedar Falls, Iowa.

But, some argue that Clinton's change of heart on the issue is a tactic campaign move rather than a sincere one.

During her 2008 presidential campaign, Clinton defended her decision to support the Iraqi war. The U.S. President Barack Obama, who was also looking to get the Democratic Party nomination to run for elections, had made his opposition to the Iraqi war during his time in the the U.S. Senate, a running campaign pillar.

The Iraq war has become one of the main issues during presidential campaigns in the U.S.

In a Gallup survey in 2014, more than 73 percent of Democrat voters said that the war was a mistake, and more than 57 percent of the U.S. population agreed it was a mistake.

Former President George W. Bush argued that the war was vital for destroying Weapons of Mass Destruction that then Iraqi President Saddam Hussein possessed.

In recent years however, the U.S. has admitted that the U.S. intelligence agency did not in fact have any evidence supporting the claim that Iraq had WMDs.

Despite her attempt to show regret for the support of the Iraq war, her record over the years suggests that she more often than not supports a troops-on-ground strategy in conflicts. When Clinton served as the Secretary of State under the Obama administration, she helped orchestrate air attacks on Libya that assisted in bringing down Moammar Gadhafi, unleashing a civil war that is still raging.

In 2013, after she left office, she supported U.S. military action against the Syrian regime, a course that President Obama eventually backed away from.

Clinton's support of military interventions was highlighted yet again when she last year criticized Obama's Syria policy.

“The failure to help build up a credible fighting force of the people who were the originators of the protests against Assad—there were Islamists, there were secularists, there was everything in the middle—the failure to do that left a big vacuum, which the jihadists have now filled,” Clinton told The Atlantic in August.